Sensor stack venting

ABSTRACT

Sensor stack venting techniques are described. In one or more implementations, one or more vent structures are formed within layers of a pressure sensitive sensor stack for a device. Vent structures including channels, holes, slots, and so forth are designed to provide pathways for gas released by feature elements to escape. The pathways may be arranged to convey outgases through the layers to designated escape points in a controlled manner that prevents deformities typically caused by trapped gases. The escape points in some layers enable at least some other layers to be edge-sealed. Pathways may then be formed to convey gas from the edge-sealed layer(s) to an edge vented layer(s) having one or more escape points, such that feature elements in the edge-sealed layer(s) remain protected from contaminants.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to the following U.S. Provisional Patent Applications, the entire disclosures of each of these applications being incorporated by reference in their entirety:

U.S. Provisional Patent Application No. 61/647,405, filed May 15, 2012, and titled “DFM for Assembly Process;”

U.S. Provisional Patent Application No. 61/606,321, filed Mar. 2, 2012, and titled “Screen Edge;”

U.S. Provisional Patent Application No. 61/606,301, filed Mar. 2, 2012, and titled “Input Device Functionality;”

U.S. Provisional Patent Application No. 61/606,313, filed Mar. 2, 2012, and titled “Functional Hinge;”

U.S. Provisional Patent Application No. 61/606,333, filed Mar. 2, 2012, and titled “Usage and Authentication;”

U.S. Provisional Patent Application No. 61/613,745, filed Mar. 21, 2012, and titled “Usage and Authentication;”

U.S. Provisional Patent Application No. 61/606,336, filed Mar. 2, 2012, and titled “Kickstand and Camera;” and

U.S. Provisional Patent Application No. 61/607,451, filed Mar. 6, 2012, and titled “Spanaway Provisional.”

This application also incorporates the following application by reference in their entirety: U.S. patent application Ser. No. 13/595,700, filed Aug. 27, 2012, and titled “Input Device Manufacture,” U.S. patent application Ser. No. 13/470,633, filed May 14, 2012, and titled “Flexible Hinge and Removable Attachment” and U.S. patent application Ser. No. 13/471,237, filed May 14, 2012, and titled “Flux Fountain.”

BACKGROUND

Mobile computing devices have been developed to increase the functionality that is made available to users in a mobile setting. For example, a user may interact with a mobile phone, tablet computer, or other mobile computing device to check email, surf the web, compose texts, interact with applications, and so on. Some mobile computing devices are constructed using sheets of various materials that are laminated together to form a stack of layers. Various functionality for a mobile computing device such as keys, sensors, graphics, labels, and/or other feature elements may be formed within such layers using a variety of techniques.

In some instances, solvents used to form feature elements may be trapped and create gases that may produce deformities (e.g. bubbles, voids, expansion of layer spacing, and so forth) in the stack of layers if the gases are not properly expelled. One traditional technique to enable gases released by feature elements to escape involves leaving the edges of layers unsealed. However, unsealed edges may allow contaminants to enter in between the layers, which may damage components within the layers and/or degrade device performance.

SUMMARY

Sensor stack venting techniques are described. In one or more implementations, vent structures are formed within layers of a pressure sensitive sensor stack for a device. Vent structures including channels, holes, slots, and so forth are designed to provide pathways for gas released by feature elements to escape. The pathways may be arranged to convey outgases through layers to escape points (e.g., vents) in a controlled manner that prevents deformities typically caused by trapped gases. The escape points in some layers enable at least some other layers to be edge-sealed. Pathways may then be formed to convey gas from the edge-sealed layer(s) to an edge vented layer(s) having one or more escape points, such that feature elements in the edge-sealed layer(s) remain protected from contaminants.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. Entities represented in the figures may be indicative of one or more entities and thus reference may be made interchangeably to single or plural forms of the entities in the discussion.

FIG. 1 is an illustration of an environment in an example implementation that is operable to employ the techniques described herein.

FIG. 2 depicts an example implementation of an input device of FIG. 1 as showing a flexible hinge in greater detail.

FIG. 3 depicts an example implementation showing a perspective view of a connecting portion of FIG. 2 that includes mechanical coupling protrusions and a plurality of communication contacts.

FIG. 4 depicts a plurality of layers of the input device of FIG. 2 in a perspective exploded view.

FIG. 5 depicts an example of a cross-sectional view of a pressure sensitive key of a keyboard of the input device of FIG. 2.

FIG. 6A depicts an example of a pressure sensitive key of FIG. 5 as having pressure applied at a first location of a flexible contact layer to cause contact with a corresponding first location of a sensor substrate.

FIG. 6B depicts an example of the pressure sensitive key of FIG. 5 as having pressure applied at a second location of the flexible contact layer to cause contact with a corresponding second location of the sensor substrate.

FIG. 7 depicts an example of surface mount hardware elements that maybe used to support functionality of the input device of FIG. 1.

FIG. 8 illustrates an example implementation in which the surface mount hardware element of FIG. 7 is depicted as being nested in one or more layers of the input device.

FIG. 9 depicts a cross section view of representative layers that may be included in the assembly of FIG. 4 showing example vent structures disposed in the layers.

FIG. 10 depicts a top view of a portion of a layer in which vent structures and escape points may be formed using various techniques.

FIG. 11 is a diagram that illustrates aspects of sensor stack venting for multiple layers.

FIG. 12 depicts an example procedure for forming vent structures in accordance with one or more implementations.

FIG. 13 illustrates an example system including various components of an example device that can be implemented as any type of computing device as described with reference to the other figures to implement the techniques described herein.

DETAILED DESCRIPTION

Overview

Solvents used to form feature elements in an accessory device (such as a flexible keyboard/cover accessory) may be trapped in layers of material used to form the device and create gases that may produce deformities in the stack of layers if the gases are not properly expelled. Traditionally, gases are vented by keeping the edges of the layers unsealed, but this approach may leave sensitive components within the layers susceptible to contamination.

Sensor stack venting techniques are described. In one or more implementations, vent structures are formed within layers of a pressure sensitive sensor stack for an accessory device. Vent structures including channels, holes, slots, and so forth are designed to provide pathways for gas released by feature elements to escape. The vent structures may be formed using various techniques including but not limited to die-cutting, laser etching, chemical etching, masking, mechanical force (e.g., drilling, grinding, punching, etc.), arrangement of adhesive/spacing materials, and so forth. The pathways that are formed may be arranged to convey outgases through the layers to designated escape points (e.g., vents) in a controlled manner that prevents deformities typically caused by trapped gases. The escape points may be exposed to an exterior of the assembly to allow gases to escape. The escape points are placed in some layers and thereby enable at least some other layers to be edge-sealed. For example, pathways may be formed to convey gas from an edge-sealed layer(s) to an edge vented layer(s) having one or more designated escape points, such that feature elements in the edge-sealed layer(s) remain protected from contaminants. In this way, particular layers having components that may be sensitive to contaminants may be substantially sealed while still enabling gas to escape via vent structures and designated escape points disposed throughout the plurality of layers.

In the following discussion, an example environment is first described that may employ the techniques described herein. Example devices and procedures are then described which may be employed in the example environment as well as other environments. Consequently, the example devices and procedures are not limited to the example environment and the example environment may also include other devices and implement other procedures. Further, although an accessory device configured as an input device is described in some examples, other accessory devices are also contemplated that do not include input functionality, such as covers, displays, a battery, and so forth.

Example Environment

FIG. 1 is an illustration of an environment 100 in an example implementation that is operable to employ the techniques described herein. The illustrated environment 100 includes an example of a computing device 102 that is physically and communicatively coupled to an input device 104 (e.g., an accessory device) via a flexible hinge 106. The computing device 102 may be configured in a variety of ways. For example, the computing device 102 may be configured for mobile use, such as a mobile phone, a tablet computer as illustrated, and so on. Thus, the computing device 102 may range from full resource devices with substantial memory and processor resources to a low-resource device with limited memory and/or processing resources. The computing device 102 may also relate to software that causes the computing device 102 to perform one or more operations.

The computing device 102, for instance, is illustrated as including an input/output module 108. The input/output module 108 is representative of functionality relating to processing of inputs and rendering outputs of the computing device 102. A variety of different inputs may be processed by the input/output module 108, such as inputs relating to functions that correspond to keys of the input device 104, keys of a virtual keyboard displayed by the display device 110 to identify gestures and cause operations to be performed that correspond to the gestures that may be recognized through the input device 104 and/or touchscreen functionality of the display device 110, and so forth. Thus, the input/output module 108 may support a variety of different input techniques by recognizing and leveraging a division between types of inputs including key presses, gestures, and so on.

In the illustrated example, the input device 104 is an accessory device configured as a keyboard having a QWERTY arrangement of keys although other arrangements of keys are also contemplated. Further, other non-conventional configurations for input devices/accessory devices are also contemplated, such as a game controller, configuration to mimic a musical instrument, and so forth. Thus, the input device 104 and keys incorporated by the input device 104 may assume a variety of different configurations to support a variety of different functionality. Different accessory devices may be connected to the computing device at different times.

As previously described, the input device 104 is physically and communicatively coupled to the computing device 102 in this example through use of a flexible hinge 106. The flexible hinge 106 is flexible in that rotational movement supported by the hinge is achieved through flexing (e.g., bending) of the material forming the hinge as opposed to mechanical rotation as supported by a pin, although that implementation is also contemplated. Further, this flexible rotation may be configured to support movement in one direction (e.g., vertically in the figure) yet restrict movement in other directions, such as lateral movement of the input device 104 in relation to the computing device 102. This may be used to support consistent alignment of the input device 104 in relation to the computing device 102, such as to align sensors used to change power states, application states, and so on.

The flexible hinge 106, for instance, may be formed using one or more layers of fabric and include conductors formed as flexible traces to communicatively couple the input device 104 to the computing device 102 and vice versa. This communication, for instance, may be used to communicate a result of a key press to the computing device 102, receive power from the computing device, perform authentication, provide supplemental power to the computing device 102, and so on. The flexible hinge 106 may be configured in a variety of ways, further discussion of which may be found in relation to the following figure. Other kinds of connections and interfaces to couple an input device 104 to the computing device 102 are also contemplated.

FIG. 2 depicts an example implementation 200 of the input device 104 of FIG. 1 as showing the flexible hinge 106 in greater detail. In this example, a connection portion 202 of the input device is shown that is configured to provide an interface for communicative and physical connection between the input device 104 and the computing device 102. In this example, the connection portion 202 has a height and cross section configured to be received in a channel in the housing of the computing device 102, although this arrangement may also be reversed without departing from the spirit and scope thereof.

The connection portion 202 is flexibly connected to a portion of the input device 104 that includes the keys through use of the flexible hinge 106. Thus, when the connection portion 202 is physically connected to the computing device the combination of the connection portion 202 and the flexible hinge 106 supports movement of the input device 104 in relation to the computing device 102 that is similar to a hinge of a book.

For example, rotational movement may be supported by the flexible hinge 106 such that the input device 104 may be placed against the display device 110 of the computing device 102 and thereby act as a cover. The input device 104 may also be rotated so as to be disposed against a back of the computing device 102, e.g., against a rear housing of the computing device 102 that is disposed opposite the display device 110 on the computing device 102.

Naturally, a variety of other orientations are also supported. For instance, the computing device 102 and input device 104 may assume an arrangement such that both are laid flat against a surface as shown in FIG. 1. In another instance, a typing arrangement may be supported in which the input device 104 is laid flat against a surface and the computing device 102 is disposed at an angle to permit viewing of the display device 110, e.g., such as through use of a kickstand disposed on a rear surface of the computing device 102. Other instances are also contemplated, such as a tripod arrangement, meeting arrangement, presentation arrangement, and so forth.

The connecting portion 202 is illustrated in this example as including magnetic coupling devices 204, 206, mechanical coupling protrusions 208, 210, and a plurality of communication contacts 212. The magnetic coupling devices 204, 206 are configured to magnetically couple to complementary magnetic coupling devices of the computing device 102 through use of one or more magnets. In this way, the input device 104 may be physically secured to the computing device 102 through use of magnetic attraction.

The connecting portion 202 also includes mechanical coupling protrusions 208, 210 to form a mechanical physical connection between the input device 104 and the computing device 102. The mechanical coupling protrusions 208, 210 are shown in greater detail in the following figure.

FIG. 3 depicts an example implementation 300 shown a perspective view of the connecting portion 202 of FIG. 2 that includes the mechanical coupling protrusions 208, 210 and the plurality of communication contacts 212. As illustrated, the mechanical coupling protrusions 208, 210 are configured to extend away from a surface of the connecting portion 202, which in this case is perpendicular although other angles are also contemplated.

The mechanical coupling protrusions 208, 210 are configured to be received within complimentary cavities within the channel of the computing device 102. When so received, the mechanical coupling protrusions 208, 210 promote a mechanical binding between the devices when forces are applied that are not aligned with an axis that is defined as correspond to the height of the protrusions and the depth of the cavity.

For example, when a force is applied that does coincide with the longitudinal axis described previously that follows the height of the protrusions and the depth of the cavities, a user overcomes the force applied by the magnets solely to separate the input device 104 from the computing device 102. However, at other angles the mechanical coupling protrusion 208, 210 are configured to mechanically bind within the cavities, thereby creating a force to resist removal of the input device 104 from the computing device 102 in addition to the magnetic force of the magnetic coupling devices 204, 206. In this way, the mechanical coupling protrusions 208, 210 may bias the removal of the input device 104 from the computing device 102 to mimic tearing a page from a book and restrict other attempts to separate the devices.

The connecting portion 202 is also illustrated as including a plurality of communication contacts 212. The plurality of communication contacts 212 is configured to contact corresponding communication contacts of the computing device 102 to form a communicative coupling between the devices. The communication contacts 212 may be configured in a variety of ways, such as through formation using a plurality of spring loaded pins that are configured to provide a consistent communication contact between the input device 104 and the computing device 102. Therefore, the communication contact may be configured to remain during minor movement of jostling of the devices. A variety of other examples are also contemplated, including placement of the pins on the computing device 102 and contacts on the input device 104.

FIG. 4 depicts a plurality of layers of the input device 104 in a perspective exploded view 400. At top, an outer layer 402 is shown which may be configured using a fabric enclosure assembly (e.g., 0.6 millimeter polyurethane) in which embossing (or other techniques) is used to provide representations of various elements including underlying input keys as well as representations of respective functions of the keys. Embossing or other techniques may also provide representations of logos, a legend, labels, borders, images, and/or other graphical elements. A force concentrator 404 may be disposed beneath the outer layer 402. The force concentrator 402 may be configured to provide a mechanical filter, force direction, and to hide witness lines of underlying components. Below the force concentrator 404 in this example is a pressure sensitive sensor stack 406. The pressure sensitive sensor stack 406 may include layers used to implement pressure sensitive keys and other feature elements to provide accessory functionality, as further described in the “Pressure Sensitive Sensor Stack and Layer Details” section below. In accordance with techniques described herein, various vent structures may be formed within the pressure sensitive sensor stack 406 (and/or other layers) to facilitate venting of gas from the assembly depicted in FIG. 4. Vent structures may be formed and arranged in various ways details of which are discussed in relation to the following figures.

A support layer 408 is illustrated below the pressure sensitive sensor stack 406 assembly. The support layer 408 is configured to support the flexible hinge 106 and conductors included therein from damage. An adhesive layer 410 is illustrated as disposed beneath the support layer 408 and above a support board 412 which is configured to add mechanical stiffness to an input portion of the input device 104. The adhesive layer 410 may be configured in a variety of ways to secure the support board 412 to the support layer 408. The adhesive layer 410, for instance, may be configured to include a dot matrix of adhesive on both sides of the layer. Therefore, air/gas may be permitted to escape as the layers are rolled together, thereby reducing wrinkles and air bubbles between the layers. Thus, selective arrangement of adhesive in one or more layers provides one mechanism in which vent structures may be formed to convey outgases. Other spacing materials may be employed in addition to or in lieu of using adhesive.

Furthermore, channels, holes, slots and other vent structures may be formed within different example layers of FIG. 4 in various ways including but not limited to die-cutting, laser etching, chemical etching, masking, mechanical force (e.g., drilling, grinding, punching, etc.), arrangement of spacing materials, and so forth. Vent structures created in these and other ways may be arranged throughout the layers and aligned between the layers when stacked together to produce pathways through the layers for gas to escape. The pathways may be employed to convey outgas from elements formed in the layers and direct the outgas to designated escape points that may be exposed to an exterior of the stack, assembly, and/or device to allow gases to escape. As mentioned, this enables conveyance of gas from edge-sealed layers through pathways to “vented” layers having the designated escape points.

In this manner, gas formed by solvents used in the manufacture of the device is allowed to escape while components formed in some layers may still be protected from contaminants by edge sealing these layers. To put this another way, vents may be selectively placed in some layers and not in other layers to protect particular layers having sensitive components from external contamination. Generally the vented layers may be selected because they contain components that are less sensitive to contaminants than components in other layers. These and other techniques to form and make use of vent structures are discussed in relation to the following figures.

In the illustrated example, the adhesive layer 410 also includes a nesting channel configured to support flexible printed circuit routing, e.g., between controllers, sensors, or other modules and the pressure sensitive keys and/or communication contacts of the connection portion 202. Beneath the support board 412 is a backer layer 414 with PSA and an outer surface 416. The outer surface 416 may be formed from a material that is the same as or different from the other outer surface 402.

Pressure Sensitive Sensor Stack and Layer Details

FIG. 5 depicts an example of a cross-sectional view of a pressure sensitive key 500 of a keyboard of the input device 104 of FIG. 2 that forms the pressure sensitive sensor stack 406. The pressure sensitive key 500 in this example is illustrated as being formed using a flexible contact layer 502 (e.g., Mylar) that is spaced apart from the sensor substrate 504 using a spacer layer 508, 408, which may be formed as another layer of Mylar, formed on the sensor substrate 504, and so on. In this example, the flexible contact layer 502 does not contact the sensor substrate 504 absent application of pressure against the flexible contact layer 502. The pressure sensitive key is one example of a feature element that may be implemented by layers that form a fabric enclosure assembly. Other examples of feature elements include but are not limited to controls, labels, graphics, and sensor elements (e.g., proximity sensor, accelerometer, gyroscope, temperature sensor, magnetometer, GPS, radios, and so forth).

The flexible contact layer 502 in this example includes a force sensitive ink 510 disposed on a surface of the flexible contact layer 502 that is configured to contact the sensor substrate 504. The force sensitive ink 510 is configured such that an amount of resistance of the ink varies directly in relation to an amount of pressure applied. The force sensitive ink 510, for instance, may be configured with a relatively rough surface that is compressed against the sensor substrate 504 upon an application of pressure against the flexible contact layer 502. The greater the amount of pressure, the more the force sensitive ink 510 is compressed, thereby increasing conductivity and decreasing resistance of the force sensitive ink 510. Other conductors may also be disposed on the flexible contact layer 502 without departing form the spirit and scope therefore, including other types of pressure sensitive and non-pressure sensitive conductors.

The sensor substrate 504 includes one or more conductors 512 disposed thereon that are configured to be contacted by the force sensitive ink 510 of the flexible contact layer 502. When contacted, an analog signal may be generated for processing by the input device 104 and/or the computing device 102, e.g., to recognize whether the signal is likely intended by a user to provide an input for the computing device 102. A variety of different types of conductors 512 may be disposed on the sensor substrate 504, such as formed from a variety of conductive materials (e.g., silver, copper), disposed in a variety of different configurations, and so on.

FIG. 6A depicts an example 600 of the pressure sensitive key 500 of FIG. 5 as having pressure applied at a first location of the flexible contact layer 502 to cause contact of the force sensitive ink 510 with a corresponding first location of the sensor substrate 504. The pressure is illustrated through use of an arrow in FIG. 6A and may be applied in a variety of ways, such as by a finger of a user's hand, stylus, pen, and so on. In this example, the first location at which pressure is applied as indicated by the arrow is located generally near a center region of the flexible contact layer 502 that is disposed between the spacer layers 506, 508. Due to this location, the flexible contact layer 502 may be considered generally flexible and thus responsive to the pressure.

This flexibility permits a relatively large area of the flexible contact layer 502, and thus the force sensitive ink 510, to contact the conductors 512 of the sensor substrate 504. Thus, a relatively strong signal may be generated. Further, because the flexibility of the flexible contact layer 502 is relatively high at this location, a relatively large amount of the force may be transferred through the flexible contact layer 502, thereby applying this pressure to the force sensitive ink 510. As previously described, this increase in pressure may cause a corresponding increase in conductivity of the force sensitive ink and decrease in resistance of the ink. Thus, the relatively high amount of flexibility of the flexible contact layer at the first location may cause a relatively stronger signal to be generated in comparison with other locations of the flexible contact layer 502 that located closer to an edge of the key, an example of which is described in relation to the following figure.

FIG. 6B depicts an example 602 of the pressure sensitive key 500 of FIG. 5 as having pressure applied at a second location of the flexible contact layer 502 to cause contact with a corresponding second location of the sensor substrate 504. In this example, the second location of FIG. 6A at which pressure is applied is located closer to an edge of the pressure sensitive key (e.g., closer to an edge of the spacer layer 508) than the first location of FIG. 5. Due to this location, the flexible contact layer 502 has reduced flexibility when compared with the first location and thus less responsive to pressure.

This reduced flexibility may cause a reduction in an area of the flexible contact layer 502, and thus the force sensitive ink 510, that contacts the conductors 512 of the sensor substrate 504. Thus, a signal produced at the second location may be weaker than a signal produced at the first location of FIG. 6A.

Further, because the flexibility of the flexible contact layer 502 is relatively low at this location, a relatively low amount of the force may be transferred through the flexible contact layer 502, thereby reducing the amount of pressure transmitted to the force sensitive ink 510. As previously described, this decrease in pressure may cause a corresponding decrease in conductivity of the force sensitive ink and increase in resistance of the ink in comparison with the first location of FIG. 5. Thus, the reduced flexibility of the flexible contact layer 502 at the second location in comparison with the first location may cause a relatively weaker signal to be generated. Further, this situation may be exacerbated by a partial hit in which a smaller portion of the user's finger is able to apply pressure at the second location of FIG. 6B in comparison with the first location of FIG. 6A.

FIG. 7 depicts an example 700 of surface mount hardware elements 702 that may be used to support functionality of the input device 104. The input device 104 may be configured in a variety of ways to support a variety of functionality. For example, the input device 104 may be configured to include pressure sensitive keys as described in relation to FIGS. 5-7, a track pad as shown in FIG. 1, or other functionality such as mechanically switched keys, a biometric reader (e.g., fingerprint reader), and so on.

Accordingly, the input device 104 may include a variety of different types of surface mount hardware elements 702 (e.g., feature elements) to support this functionality. For example, the input device 104 may include a processor 704 which may be leveraged to perform a variety of different operations. An example of such an operation may include processing signals generated by the pressure sensitive keys 500 of FIG. 5 or other keys (e.g., mechanically switched keys that are not pressure sensitive) into a human interface device (HID) compliant input, such as to identify a particular keystroke. Thus, in this example the input device 104 may perform the processing of the signals and provide a result of this processing as an input to the computing device 102. In this way, the computing device 102 and software thereof may readily identify the inputs without modification, such as by an operating system of the computing device 102.

In another example, the input device 104 may include one or more sensors 706. The sensors 706, for instance, may be leveraged to detect movement and/or an orientation of the input device 104. Examples of such sensors 706 include accelerometers, magnetometers, inertial measurement units (IMUs), and so forth.

In a further example, the input device 104 may include a touch controller 708, which may be used to process touch inputs detected using one or more keys of the keyboard, the track pad, and so forth. In yet a further example, the input device 104 may include one or more linear regulators 710 to maintain a relatively steady voltage for electrical components of the input device 104.

The input device 104 may also include an authentication integrated circuit 712. The authentication integrated circuit 712 may be configured to authenticate the input device 104 for operation with the computing device 102. This may be performed in a variety of ways, such as to share secrets between the devices that are processed by the input device 104 and/or the computing device 102 to perform the authentication. A variety of other 714 surface mount hardware elements 702 are also contemplated to support a variety of different functionality.

As previously described, however, inclusion of the surface mount hardware elements 702 using conventional techniques may have an adverse effect on an overall thickness of the input device 104. However, in one or more implementations described herein layers of the input device 104 may include nesting techniques to mitigate this effect, further discussion of which may be found in relation to the following figure.

FIG. 8 illustrates an example implementation 800 in which the surface mount hardware element 1802 of FIG. 18 is depicted as being nested in one or more layers of the input device 104. As previously described, the input device may include top and bottom outer layers 402, 416 which may be formed to have a desirable tactile feel to a user, such as through formation using microfiber, and so on. The outer layer 402, for instance, may be configured using an embossed fabric (e.g., 0.6 millimeter polyurethane) in which the embossing is used to provide indications of underlying keys as well as indications of respective functions of the keys.

A force concentrator 404 may be disposed beneath the outer layer 402 that may include a force concentrator layer and a plurality of pads to support respective pressure sensitive keys implemented via underlying layers. The force concentrator 404 may be configured to provide a mechanical filter, force direction, and to hide witness lines of underlying components.

A pressure sensitive sensor stack 406 is disposed beneath the force concentrator 404 in this example, although other examples are also contemplated in which a force concentrator 404 is not utilized. The pressure sensitive sensor stack 406 includes layers used to implement pressure sensitive keys and/or other feature elements. As described in FIG. 5, for instance, the flexible contact layer 502 may include a force sensitive ink, which through flexing the flexible contact layer 502 may contact one or more conductors of the sensor substrate 504 to generate a signal usable to initiate an input.

The sensor substrate 504 may be configured in a variety of ways. In the illustrated example, the sensor substrate 504 includes a first side on which the one or more conductors are configured, such as through implementation as traces on a printed circuit board (PCB). A surface mount hardware element 702 is mounted to second side of the sensor substrate 504 that is opposite the first side.

The surface mount hardware element 702, for instance, may be communicatively coupled through the sensor substrate 504 to the one or more conductors of the first side of the sensor substrate 504. The surface mount hardware element 702 may then process the generated signals to convert the signals to HID compliant inputs that are recognizable by the computing device 102.

This may include processing of analog signals to determine a likely intention of a user, e.g., to process miss hits, signals from multiple keys simultaneously, implement a palm rejection threshold, determine if a threshold has been exceeded that is indicative of a likely key press, and so on. As previously described in relation to FIG. 7, a variety of other examples of functionality that may be implemented using surface mount hardware elements of the input device 104 are contemplated without departing from the spirit and scope thereof.

In order to reduce an effect of a height the surface mount hardware element 702 on an overall thickness of the input device 104, the surface mount hardware element 702 may disposed through one or more holes of other layers of the input device 104. In this example, the surface mount hardware element 702 is disposed through holes that are made through the support layer 408 and the adhesive layer 410 and at least partially through the support board 412. Another example is also illustrated in FIG. 4 in which holes are formed entirely through each of the support layer 408, adhesive layer 410, and the support board 412.

Thus, in this example an overall thickness of the layers of the input device 104 of the force concentrator 404 through the backer layer 414 and the layers disposed in between may be configured to have a thickness of approximately 2.2 millimeters or less. Additionally, depending on the thickness of the material chosen for the outer layers 402, 416 the overall thickness of the input device 104 at a pressure sensitive key may be configured to be approximately at or below three and a half millimeters. Naturally, other thicknesses are also contemplated without departing from the spirit and scope thereof.

Sensor Stack Venting

In context of the forgoing discussion of example devices and assembly techniques, techniques for sensor stack venting are now discussed in relation to FIGS. 9 to 12. In general, channels, holes, slots and other vent structures may be formed within different example layers of FIG. 4 in various ways including, but not limited to, placement of adhesive and/or other spacing material, die-cutting, laser etching, chemical etching, masking, mechanical force (e.g., drilling, grinding, punching, etc.), and so forth. Vent structures created in these and other ways may be arranged throughout layers used to form an input device/accessory device as described previously. Vent structures disposed throughout a plurality layers may then be aligned when the layers are stacked together to produce pathways for gas to escape. In this manner, gas formed by solvents used in the manufacture of the device is allowed to escape via the vent structure pathways while components formed in some layers may still be protected from contaminants by edge sealing these layers.

To illustrate, consider FIG. 9 which depicts generally at 900 a diagram showing vent structures formed within an example layer assembly. In particular, a plurality of representative layers which may be laminated to form an accessory device (e.g., input device 104) are shown as including layer A 902, layer B 904, layer C 906, and layer D 908. The layers may represent layers of a pressure sensitive sensor stack as previously described. In addition or alternatively, the layers may represent layers of a fabric enclosure assembly as described in relation to FIG. 4 and elsewhere herein.

Various vent structures 910 are also depicted as being formed with the example layers. The vent structure may be formed within and between different layers. The vent structures 910 may include channels, holes, slots, walls, applied adhesive/spacer material structures, protrusions, indentations, voids, and so forth. Vent structures 910 may also be formed using any suitable technique.

For example, vent structures 910 may include a matrix of applied adhesive and/or spacer material that creates a controlled gap between layers. Voids within the matrix may be formed in various ways to act as vent structures between the layers. The voids may be formed by selective placement of the adhesive and/or spacer material such that voids are created in selected areas when the layers are laminated together. For example, voids may be selectively produced to act as vents when screen printing material to bind the layers and/or provide support between the layers. Voids may also be formed after application of the adhesive and/or spacer material by etching, grinding, cutting, punching, and other techniques. In addition or alternatively, other vent structures 910 may be formed generally by removing material from one or more layers to produce the vent structures 910. This may be accomplished by die-cutting, laser etching, chemical etching, masking, mechanical force (e.g., drilling, grinding, punching, etc.), and/or other suitable techniques to form holes, channels, slots and other structures in the layers. Thus, a variety of different types of vent structures may be formed using different techniques.

Vent structures 910 within the layers may be aligned and joined together when layers are laminated together to form pathways for gases that may be released from feature elements disposed within the layers to escape. By way of example, the feature elements may include screen printed elements such as pressure sensitive keys, controls, labels, graphics, sensor elements and so forth. Solvents and inks used to create such feature elements may remain in the features during manufacture even after curing. As such, the solvents and inks may evaporate thereby releasing gas within the layers when layers are laminated together. Effectively, the vent structures may be constructed to plumb/direct the gas in and between the layers to particular escape points or “vents.” Vent structures across different layers may be connected one to another to form pathways to the escape points on vented layers. Different types of vent structures described herein may be employed individually and/or in various combinations to form respective pathways.

For example, holes placed in some layers may connect to slots, channels, and/or additional holes in other layers that operate as escape points. For example, FIG. 9 depicts holes in layer A 902 as being aligned with slots in layer B 904 to facilitate transmission of gas from layer A 902 to layer B 904 and out of the assembly. Holes in layer C 906 and layer D 908 similarly align to direct outgas to layer B 904. In the illustrated example, layer A 902 is depicted as a sealed layer 912 and layer B 904 is depicted as a vented layer 914 having designated escape points 916 to expel gases. Layer C 906 and layer D 908 are also represented as sealed layers 912 that do not contain escape points 916.

The vent structures may accordingly be designed and employed to route gas from one or more sealed layers 912 to escape points 916 in one or more vented layers as shown in FIG. 9. The escape points 916 may include edge vents and accordingly a vented layer may be considered an edge-vented layer in some scenarios. In contrast, a sealed layer 912 may be considered an edge-sealed layer when taken in comparison to an edge-vented layer.

FIG. 10 depicts generally at 1000 formation of vent structures within an example layer 1002. In the depicted example, the layer 1002 includes a plurality of feature elements 1004. By way of example, the feature elements 1004 may be configured as pressure sensitive keys for an accessory device configured as a keyboard to provide keyboard functionality. The layer 1002 may represent a layer within a pressure sensitive sensor stack that implements the pressure sensitive keys. Vent structures within other layers as described above and below may be formed in a comparable manner. Here, a spacer support 1006 is depicted as being disposed along one or more edges of the layer 1002. The spacer support 1006 may be formed by way of adhesive and/or spacer material that is applied to bind the layer 1002 to other layers and/or provide support between the layers. The spacer support 1006 may also be configured to maintain a controlled gap between the layer 1002 and another layer to which the layer 1002 is joined.

The spacer support 1006 may be formed by applying the adhesive and/or spacer material along the edges. This may occur in any suitable way. In one approach, material is screen printed along the edges to form the spacer support 1006. Note that at least some of feature elements 1004 within the layer may also be produced by screen printing. Other techniques to apply adhesive/spacer material and/or form feature elements 1004 are also contemplated.

In the course of applying adhesive and/or spacer material to form the spacer support 1006, voids may be placed at designated locations to produce vent structures 910 and/or escape points 916. In one approach, voids may be created by preventing application of material in selected areas. This may occur by turning off the flow of material, masking selected areas, and so forth. Voids may also be created by removing material in selected areas after the material is applied.

By way of example, a vent structure 910 is shown in FIG. 10 that is configured as a notch in the spacer support 1006 that extends partially through the spacer support 1006. The notch may align with vent structures in other layers to enable transmission of gas from the layer 1002 to escape points (e.g., vents) in one or more vented layers. FIG. 10 also depicts an example escape point 916 configured as a slot that extends through the spacer support 1006 to the exterior of the layer. The example slot allows gas formed by feature elements 1004 to vent out of the assembly. The example slot may also be aligned with vent structures formed in other layers to receive gas conveyed from the other layers and provide a mechanism for the gas to escape in the layer 1002.

As illustrated, a layer may include both escape points 916 within the particular layer and vent structures 910 that provide pathways to vents in other layers. In addition, some layers may be substantially closed, sealed layers that may have vent structures 910 but do not contain escape points 916 (e.g., un-vented layers). Still further, a layer may be a designated vented layer that has escape points 916, but does not contain vent structures 910 configured to provide pathways to vents/escape points in other layers.

FIG. 11 depicts generally at 1100 a diagram that illustrates additional aspects of sensor stack venting for multiple layers. In particular, FIG. 11 depicts layer E 1102 and layer F 1104 that are representative of two layers in a stack or assembly that may be laminated one to another. The example layers may be implemented as part of a pressure sensitive sensor stack as described herein. More generally, the layers may represent any layers used to construct an input device 104 or other accessory device as described above and below. For the purpose of illustration, the layer E 1102 is shown as a vented layer 914 that includes a plurality of escape points 916. In particular, the escape points 916 are various slots of different sizes that are formed in an edge of layer. Layer E 1102 may therefore be considered an edge-vented layer.

Further, layer F 1104 represents a sealed layer 912 (or partially sealed layer) that includes a plurality of vent structures 910 to convey gas to other layers for venting. Specifically, vent structures 910 of layer F 1104 are configured to align in the stack with respective escape points 916 in layer E 1102 as illustrated by arrow 1106 and arrow 1108. Although, some edge vents may also be included in the layer F 1104 as shown, at least some components or feature elements contained in layer F 1104 may be sealed within the layer. Thus, vent structures 910 are positioned and relied upon to enable gas from the sealed feature elements to vent to layer E 1102 and escape via corresponding escape points 916.

Assembly of an accessory device that includes layers such as those depicted in FIG. 11 may involve alignment of vent structures 910 and escape points 916 across the layers. This produces the pathways that permit gas to escape and therefore may prevent deformities that may occur if gas becomes tapped in the layers.

The use of vent structures 910 and escape points 916 disposed across various layers enables a device designer to tightly control the manner in which venting occurs. This includes but is not limited to controlling placement of vents/escape points, routing through the layers and feature elements, and the size of vents and vent structures, to name a few example.

As mentioned, placement of vents/escape points may be controlled to substantially reduce or eliminate contaminants from reaching sensitive features elements. To do so, escape points 916 may be selectively placed on some layers and piped with vent structures to layers having sensitive features elements. Some layers may remain sealed in as much as the layers do not include escape points 916. Other partially sealed layers may have a combination of vents used for some components/elements as well as some vent structures 910 used to route gas to vents in other layers. In this approach, selected components/elements of a partially sealed layer and/or sections of the layer may be sealed off from other sections having vents. In other words, the partially sealed layer may have a combination of vented sections that make use of escape points placed within the layer and sealed sections that route gas to other layers.

Still further, one or more designated vent layers may be implemented for some devices. A designated vent layer may be configured as a layer that does not contain sensitive components/elements. For instance, the designated vent layer may be configured as a support layer or spacer layer that may also protect other layers. A plurality of escape points 916 may be included in the designated vent layer and connected through vent structures 910 to other layers to enable gas from a plurality of layers to escape. Additionally, the designated vent layers may include a variety of control structures and materials that act as barriers to contaminants that may enter through the escape points. Such structures may include screening elements, filters, moisture absorbing elements, maze structures, and other structures designed to prevent dust, debris, moisture, and other contaminants from reaching other layers of the device.

Fairly elaborate pathways may be designed that act as barriers to prevent contaminants from reaching particular layers and feature elements. Thus, the techniques described herein provide a device designer a great deal of flexibility to select where vents are located and the manner in which vent structures 910 route gases through the layers.

Further, the size and shape of the various structures 910 and escape points 916 may also be controlled. The size and shape may be selected to provide sufficient venting with a minimum number of vents and such that no witness lines from the vent structures are evident on the outer surface(s) of the stacked layers. To illustrate this, various different sized holes and slots are represented in FIG. 11. Within the “sealed” layer, layer F 1104, generally smaller holes that route to other layers are employed. In the “vented” layer, layer E 1102, relatively larger holes and slots are depicted as the feature elements in this layer may be less sensitive to contamination.

Additionally, escape points 916 (e.g., vents) may be designed to span across multiple layers. This may enable fewer escape points 916 to handle venting of gases from multiple other layers. Consider for example layers that have individual thicknesses of 130 microns. Structures that act as vents/escape points may be constructed to have widths in the range of a few millimeters (e.g., approximately 1 mm to 5 mm). An escape point configured as a 2 mm slot that extends across two such layers may be constructed to have a thickness of twice the individual layer thickness, e.g., 260 microns. Thus, the slot provides a vent area of approximately 2 mm×260 microns. In this manner, relatively large vent openings that span across multiple layers may be constructed. Because larger vents are possible using these techniques, it may be possible to use fewer vents and to space multiple vents farther apart, which further assists in preventing contamination. By way of example, multiple slots having widths in the range of a few millimeters may be spaced apart several centimeters (e.g., 2 cm to 10 cm) to provide adequate venting, minimize the number of vents, and protect against contaminants. In other words, the spacing distance for vents may be an order of magnitude greater than the width of the vents.

FIG. 12 depicts an example procedure 1200 to form vent structures for sensor stack venting in accordance with one or more implementations. Vent structures are formed within one or more of a plurality of layers of a pressure sensitive sensor stack including formation of designated escape points in at least one of the plurality of layers (block 1202). Vent structures 910 may be formed in a variety of ways and in one or more different layers as previously described. At least some of the vent structures may be configured as escape points 916 disposed in one or more layers that enable venting of gas released by feature elements in the plurality of layers. Vent structures may be formed using many different techniques including die cutting, laser cutting, and/or adhesive/spacer material placement, to name a few examples. The vent structures may be formed within layers of a fabric assembly that form an enclosure for an accessory device/input device. In one example, the vent structures are formed in layers of a pressure sensitive sensor stack included in the fabric assembly to allow gas to escape when the layers are laminated one to another during manufacturing. The vent structures may also provide venting and protection from contaminants for a finished accessory device/input device during the lifetime of the device (e.g., while the device is in use by a consumer or other user).

The pressure sensitive sensor stack is assembled to align the formed vent structures such that outgas from elements disposed in the plurality of layers is conveyed via the vent structures within the plurality of layers to the designated escape points (block 1204). For instance, vent structures 910 in different layers as represented by the examples in FIGS. 9 to 11 may be aligned as layers are laminated together to produce various pathways for gases through the assembly of layers. Pathways may be formed as combinations of holes, slots, channels and/or other structures. Generally, the pathways provide a mechanism to route outgas from feature elements to designated escape points. This enables components/elements in at least some layers to be substantially sealed off. Escape points 916 may be placed in designated vent layers and/or layers having features that are resistant to contamination. According, adequate venting may be provided by selectively placing escape points 916 in certain layers while other layers or sections within the layers may be substantially sealed to protect sensitive components/elements. Pathways may be formed between different layers to convey gases between the layers. In addition or alternatively, pathways may be contained in single layer and lead to escape points in the single layer.

Having considered some example details of sensor stack venting techniques, consider now a discussion of an example system and device in accordance with one or more implementations.

Example System and Device

FIG. 13 illustrates an example system generally at 1300 that includes an example computing device 1302 that is representative of one or more computing systems and/or devices that may implement the various techniques described herein. The computing device 1302 may be, for example, configured to assume a mobile configuration through use of a housing formed and size to be grasped and carried by one or more hands of a user, illustrated examples of which include a mobile phone, mobile game and music device, and tablet computer although other examples are also contemplated.

The example computing device 1302 as illustrated includes a processing system 1304, one or more computer-readable media 1306, and one or more I/O interface 1308 that are communicatively coupled, one to another. Although not shown, the computing device 1302 may further include a system bus or other data and command transfer system that couples the various components, one to another. A system bus can include any one or combination of different bus structures, such as a memory bus or memory controller, a peripheral bus, a universal serial bus, and/or a processor or local bus that utilizes any of a variety of bus architectures. A variety of other examples are also contemplated, such as control and data lines.

The processing system 1304 is representative of functionality to perform one or more operations using hardware. Accordingly, the processing system 1304 is illustrated as including hardware element 1310 that may be configured as processors, functional blocks, and so forth. This may include implementation in hardware as an application specific integrated circuit or other logic device formed using one or more semiconductors. The hardware elements 1310 are not limited by the materials from which they are formed or the processing mechanisms employed therein. For example, processors may be comprised of semiconductor(s) and/or transistors (e.g., electronic integrated circuits (ICs)). In such a context, processor-executable instructions may be electronically-executable instructions.

The computer-readable media 1306 is illustrated as including memory/storage 1312. The memory/storage 1312 represents memory/storage capacity associated with one or more computer-readable media. The memory/storage component 1312 may include volatile media (such as random access memory (RAM)) and/or nonvolatile media (such as read only memory (ROM), Flash memory, optical disks, magnetic disks, and so forth). The memory/storage component 1312 may include fixed media (e.g., RAM, ROM, a fixed hard drive, and so on) as well as removable media (e.g., Flash memory, a removable hard drive, an optical disc, and so forth). The computer-readable media 1306 may be configured in a variety of other ways as further described below.

Input/output interface(s) 1308 are representative of functionality to allow a user to enter commands and information to computing device 1302, and also allow information to be presented to the user and/or other components or devices using various input/output devices. Examples of input devices include a keyboard, a cursor control device (e.g., a mouse), a microphone, a scanner, touch functionality (e.g., capacitive or other sensors that are configured to detect physical touch), a camera (e.g., which may employ visible or non-visible wavelengths such as infrared frequencies to recognize movement as gestures that do not involve touch), and so forth. Examples of output devices include a display device (e.g., a monitor or projector), speakers, a printer, a network card, tactile-response device, and so forth. Thus, the computing device 1302 may be configured in a variety of ways to support user interaction.

The computing device 1302 is further illustrated as being communicatively and physically coupled to an input device 1314 that is physically and communicatively removable from the computing device 1302. In this way, a variety of different input devices may be coupled to the computing device 1302 having a wide variety of configurations to support a wide variety of functionality. In this example, the input device 1314 includes one or more keys 1316, which may be configured as pressure sensitive keys, mechanically switched keys, and so forth.

The input device 1314 is further illustrated as include one or more modules 1318 that may be configured to support a variety of functionality. The one or more modules 1318, for instance, may be configured to process analog and/or digital signals received from the keys 1316 to determine whether a keystroke was intended, determine whether an input is indicative of resting pressure, support authentication of the input device 1314 for operation with the computing device 1302, and so on.

Various techniques may be described herein in the general context of software, hardware elements, or program modules. Generally, such modules include routines, programs, objects, elements, components, data structures, and so forth that perform particular tasks or implement particular abstract data types. The terms “module,” “functionality,” and “component” as used herein generally represent software, firmware, hardware, or a combination thereof. The features of the techniques described herein are platform-independent, meaning that the techniques may be implemented on a variety of commercial computing platforms having a variety of processors.

An implementation of the described modules and techniques may be stored on or transmitted across some form of computer-readable media. The computer-readable media may include a variety of media that may be accessed by the computing device 1302. By way of example, and not limitation, computer-readable media may include “computer-readable storage media” and “computer-readable signal media.”

“Computer-readable storage media” refers to media and/or devices that enable storage of information in contrast to mere signal transmission, carrier waves, or signals per se. Thus, computer-readable storage media does not include signal bearing media or signals per se. The computer-readable storage media includes hardware such as volatile and non-volatile, removable and non-removable media and/or storage devices implemented in a method or technology suitable for storage of information such as computer readable instructions, data structures, program modules, logic elements/circuits, or other data. Examples of computer-readable storage media may include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, hard disks, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or other storage device, tangible media, or article of manufacture suitable to store the desired information and which may be accessed by a computer.

“Computer-readable signal media” refers to a signal-bearing medium that is configured to transmit instructions to the hardware of the computing device 1302, such as via a network. Signal media typically may embody computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as carrier waves, data signals, or other transport mechanism. Signal media also include any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared, and other wireless media.

As previously described, hardware elements 1310 and computer-readable media 1306 are representative of modules, programmable device logic and/or fixed device logic implemented in a hardware form that may be employed in some implementations to implement at least some aspects of the techniques described herein, such as to perform one or more instructions. Hardware may include components of an integrated circuit or on-chip system, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), and other implementations in silicon or other hardware. In this context, hardware may operate as a processing device that performs program tasks defined by instructions and/or logic embodied by the hardware as well as a hardware utilized to store instructions for execution, e.g., the computer-readable storage media described previously.

Combinations of the foregoing may also be employed to implement various techniques described herein. Accordingly, software, hardware, or executable modules may be implemented as one or more instructions and/or logic embodied on some form of computer-readable media and/or by one or more hardware elements 1310. The computing device 1302 may be configured to implement particular instructions and/or functions corresponding to the software and/or hardware modules. Accordingly, implementation of a module that is executable by the computing device 1302 as software may be achieved at least partially in hardware, e.g., through use of computer-readable media and/or hardware elements 1310 of the processing system 1304. The instructions and/or functions may be executable/operable by one or more articles of manufacture (for example, one or more computing devices 1302 and/or processing systems 1304) to implement techniques, modules, and examples described herein.

CONCLUSION

Although the example implementations have been described in language specific to structural features and/or methodological acts, it is to be understood that the implementations defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claimed features. 

What is claimed is:
 1. An apparatus comprising: a pressure sensitive sensor stack having a plurality of layers that include one or more feature elements to implement accessory functionality provided by the apparatus; one or more vent structures formed in the pressure sensitive sensor stack to convey gases released by the feature elements between the plurality of layers to designated escape points disposed in one or more of the plurality of layers; and a designated vent layer configured to include the designated escape points to handle the gases that are conveyed to the designated vent layer via the vent structures from at least one other layer of the plurality of layers.
 2. The apparatus as described in claim 1, wherein the vent structures are configured to convey the gases to at least one vented layer that contains the designated escape points from at least one sealed layer that does not contain escape points.
 3. The apparatus as described in claim 1, further comprising a connection portion configured to connect the apparatus as an accessory device to a computing device and provide the accessory functionality to the computing device when the computing device is communicatively coupled to the apparatus via the connection portion.
 4. The apparatus as described in claim 3, wherein the apparatus is configured to provide keyboard functionality and the feature elements comprise one or more pressure sensitive keys configured to convey inputs to the computing device.
 5. The apparatus as described in claim 1, wherein the one or more vent structures formed across multiple layers of the plurality of layers are aligned one to another to form pathways between the multiple layers for the gases released by the feature elements.
 6. The apparatus as described in claim 1, wherein at least some of the one or more vent structures are formed by die cutting structures in one or more of the plurality of layers.
 7. The apparatus as described in claim 1, wherein at least some of the one or more vent structures are formed by laser etching structures in one or more of the plurality of layers.
 8. The apparatus as described in claim 1, wherein at least some of the one or more vent structures are formed by selectively placing adhesive to form structures in one or more of the plurality of layers.
 9. The apparatus as described in claim 1, wherein the plurality of layers include: at least one edge-vented layer that includes one or more of the designated escape points to allow the gases to escape from the pressure sensitive sensor stack; and at least one edge-sealed layer that is substantially sealed to protect feature elements within the edge-sealed layer from contaminants.
 10. The apparatus as described in claim 1, wherein the at least some of the feature elements are formed by screen printing on the plurality of layers and the gases are produced by solvents used for the screen printing that are retained in the feature elements.
 11. The apparatus as described in claim 1, wherein the feature elements include one or more sensor elements.
 12. A method comprising: forming vent structures within one or more of a plurality of layers of a pressure sensitive sensor stack including formation of designated escape points in at least one of the plurality of layers; and assembling the pressure sensitive sensor stack to align the formed vent structures to produce pathways across multiple layers of the plurality of layers for gases released by feature elements such that the gases from the feature elements disposed in the plurality of layers are conveyed via the vent structures within the plurality of layers to the designated escape points.
 13. A method as described in claim 12, wherein the vent structures are configured to convey the gases to at least one vented layer that contains one or more of the designated escape points from at least one sealed layer that does not contain escape points so as to protect feature elements contained within the at least one sealed layer from contamination.
 14. A method as described in claim 12, wherein the vent structures comprise combinations of holes, slots, and channels that form one or more pathways between the plurality of layers to the designated escape points.
 15. A method as described in claim 12, wherein forming the one or more the vent structures comprises removing material from portions of the plurality of layers to form one or more of holes, channels, slots, or escape points.
 16. A method as described in claim 12, wherein forming the vent structures comprises selectively applying spacer material to form voids in at least one of the plurality of layers.
 17. An computing device comprising: a pressure sensitive sensor stack having a plurality of layers including: a sealed layer having one or more feature elements; a vented layer of the plurality of layers with one or more escape points exposed to an exterior of the pressure sensitive sensor stack to allow gases to escape, the escape points including edge vents spaced along an edge of the vented layer; and one or more vent structures formed in the plurality of layers to facilitate conveyance of the gases released by the feature elements in the sealed layer to the escape points in the vented layer.
 18. The computing device of claim 17, wherein the vented layer is configured as a designated vent layer having the one or more escape points and including one or more control structures to prevent contaminants from reaching the sealed layer and other layers of the plurality of layers.
 19. An apparatus comprising: a pressure sensitive sensor stack having a plurality of layers that include one or more feature elements to implement accessory functionality provided by the apparatus; and one or more vent structures formed in the pressure sensitive sensor stack to convey gases released by the feature elements between the plurality of layers to designated escape points disposed in one or more of the plurality of layers, the one or more vent structures formed across multiple layers of the plurality of layers and aligned one to another to form pathways between the multiple layers for the gases released by the feature elements.
 20. An apparatus comprising: a pressure sensitive sensor stack having a plurality of layers that include one or more feature elements to implement accessory functionality provided by the apparatus; and one or more vent structures formed in the pressure sensitive sensor stack to convey gases released by the feature elements between the plurality of layers to designated escape points disposed in one or more of the plurality of layers, the plurality of layers including: at least one edge-vented layer that includes one or more of the designated escape points to allow the gases to escape from the pressure sensitive sensor stack; and at least one edge-sealed layer that is substantially sealed to protect feature elements within the edge-sealed layer from contaminants. 